基于双混沌互扰系统的图像加密算法

Image encryption algorithm based on inter-perturbation of dual chaotic systems

针对低维混沌系统有可能退化为周期问题,以及高维混沌系统计算量大的缺陷,提出基于双混沌互扰系统的图像加密算法。通过两个简单的Logistic映射间的互扰,构造一个双混沌互扰系统。双混沌互扰系统的最大特点是扰动项同时包括常数扰动项和随机扰动项,不仅保证了系统必要的复杂性,而且增大了系统参数的取值范围。以双混沌互扰系统作为序列密钥发生器,提出一种改进的二值序列量化方法。对二值序列做随机性检验和相关性分析的结果表明,该二值序列具有良好的伪随机性和相关性,适合作为加密密钥。将其应用于图像加密的仿真实验结果也表明,该二值序列能有效且安全地掩盖明文信息,取得了较好的加密效果。

An image encryption algorithm based on inter-perturbations of dual chaotic systems was proposed for the possible degradation of low-dimensional chaotic system and the high computing work of high-dimensional chaotic system. Dual chaotic system was constructed through inter-perturbations of two simple Logistic mappings. And the most prominent feature of inter-perturbations between chaotic systems was that perturbation included constant perturbation and random perturbation simultaneously, which not only ensured the necessary system complexity, but also increased the range of system parameters. Taking dual chaotic inter-perturbed system as sequence key generator, an improved quantization method for converting chaotic sequence to binary sequence was put forward. Random testing and correlation analysis were done on binary sequence. The results show that the binary sequence has good pseudo-randomness and correlation, and appropriate to be encryption key. Simulation results of image encryption applied with the binary sequence also show that the binary sequence can cover up plaintext effectively and safely, and good encryption results are achieved.